An ocean general circulation model of the tropical Atlantic Ocean is used to study the vertically integrated vorticity equation for the annual mean flow in the Atlantic North Equatorial Countercurrent (NECC). It is found that the nonlinear terms play an important role in the vorticity budget, in the western part of the basin. Sverdrup balance does not hold in the region of the North Brazil Curr...

The effects of an oscillatory zero-net-mass-flux jet (i.e. synthetic jet) acting on a separated flow over a hump are investigated in terms of two actuation parameters – actuator position and forcing frequency. By considering the vorticity flux balance and introducing a centroid of vorticity production over the hump surface, lift and drag acting on the hump can be expressed as a function of this...

The insensitivity of the Antarctic Circumpolar Current (ACC)’s prominent isopycnal slope to changes in wind stress is thought to stem from the action of mesoscale eddies that counterbalance the wind-driven Ekman overturning—a framework verified in zonally symmetric circumpolar flows. Substantial zonal variations in eddy characteristics suggest that local dynamics may modify this balance along t...

Characteristics of near-inertial waves (NIWs) induced by the tropical storm Noul in South China Sea are analyzed based on situ observations, remote sensing, and analysis data. Remote sensing sea level anomaly data suggests that NIWs were influenced a southwestward moving anticyclonic eddy. The had comparable spectral density with internal tides, horizontal velocity 0.14–0.21 m/s. kinetic energy...

The dynamical equations of atmospheric flow are written using potential vorticity as the meridional coordinate and potential temperature as the vertical coordinate. Within this system, the atmosphere is divided into undulating tubes bounded by isentropic and constant potential vorticity surfaces, and, under adiabatic and frictionless conditions, the air moves through the tubes without penetrati...

We study sign changes and scaling laws in the Cartesian components of the velocity and vorticity of rotating turbulence, in the helicity, and in the components of vertically averaged fields. Data for the analysis are provided by high-resolution direct numerical simulations of rotating turbulence with different forcing functions, with up to 1536(3) grid points, with Reynolds numbers between ≈110...

The formation mechanism of the Santa Cruz eddy (SCE) is investigated using the fifth-generation Pennsylvania State University–National Center for Atmospheric Research Mesoscale Model (MM5). Simulations of 25–26 August 2000 showed that two eddy instances formed on that night, a finding supported by observations. The two eddies had similar behavior: they both formed in the sheltered Santa Cruz, C...

In the past most diagnostic studies of frontal cyclone development have been carried out through use of quasigeostrophic models. In this paper we present the results of vertical motions obtained from a 5-level general balance model. Nongeostrophic effects such as deformation and beta term of the balance equations, divergence, vertical advection, and the twisting term of the complete vorticity e...